Can low iron cause a woman, 69, to feel as though she is going to pass out? I can feel this problem coming on perhaps 15 minutes before it gets to the point I can t get up to walk, have clammy skin, feeling fatique. After lying down about 15 minutes, the symptoms go away. I have went to the hospital after such happenings, this is the 4th in 5 years, and they find nothing wrong at the time. Can the iron level increase within hours?